Bidirectional Communication Clusters

ABSTRACT

Methods and systems for providing bidirectional communications between client devices and server devices are described herein. Server devices in a cluster may bidirectionally communicate with client devices in a resource site via direct connections or virtual connections. One or more server devices may act as intermediate server devices for communications via virtual connections, and may distinguish different types of messages based on header contents of the messages.

FIELD

Aspects described herein generally relate to computer and networkhardware and software. More particularly, aspects of the presentdisclosure relate to methods and systems for providing bidirectionalcommunications between client devices and server devices.

BACKGROUND

Enterprises are increasingly adopting cloud computing services, whichmay provide various resources (e.g., applications and/or desktops) as aservice to users. Users may access the resources via user devices. Theresources may be hosted by client devices located in on-premises and/orcloud resource sites. Computing devices in communication with the clientdevices (e.g., computing devices implementing one or more control planefunctions for managing the client devices) may be located in a differentarea (e.g., a different network) from the client devices.

SUMMARY

The following presents a simplified summary of various aspects describedherein. This summary is not an extensive overview, and is not intendedto identify required or critical elements or to delineate the scope ofthe claims. The following summary merely presents some concepts in asimplified form as an introductory prelude to the more detaileddescription provided below.

Methods and systems for improving the performance and/or scalability ofthe communications between the client devices and the computing devicesmay be developed. Examples described herein are directed towards asystem, an apparatus, and/or computer readable media configured toperform a method for providing bidirectional communications betweenclient devices and server devices. A first computing device, of acluster of computing devices, may establish bidirectional connectionswith other computing devices of the cluster of computing devices. Thefirst computing device may establish a bidirectional connection with aclient device to form a virtual connection between the client device anda second computing device of the cluster of computing devices, whereinthe virtual connection allows bidirectional communication between theclient device and the second computing device via the first computingdevice. The first computing device may receive, from the client device,a message comprising a header that includes forwarding flag data anddestination connection data. The first computing device may send, basedon the forwarding flag data and the destination connection data, themessage to the second computing device.

In some examples, based on determining that the forwarding flag dataindicates a forwarding flag, the first computing device may determine,based on the destination connection data, a connection to the secondcomputing device. The first computing device may update the forwardingflag data with a non-forwarding flag. The non-forwarding flag mayindicate, to the second computing device, processing a payload of themessage. The first computing device may send the message, via theconnection, to the second computing device.

In some examples, the first computing device may receive, from theclient device, a second message comprising a second header that includessecond forwarding flag data. Based on determining that the secondforwarding flag data indicates a non-forwarding flag, the firstcomputing device may process a payload of the second message. In someexamples, the first computing device may determine, based on aconnection database table, that a second client device is directlyconnected to the first computing device via a second bidirectionalconnection. The first computing device may send, to the second clientdevice and via the second bidirectional connection, a second message.

In some examples, the first computing device may determine, based on aconnection database table, that a second client device is connected tothe first computing device via a virtual connection comprising a thirdcomputing device of the cluster of computing devices. The firstcomputing device may populate forwarding flag data of a second messagewith a forwarding flag. The first computing device may populatedestination connection data of the second message with a connectionbetween the third computing device and the second client device. Thefirst computing device may send, to the third computing device, thesecond message.

In some examples, the first computing device may store a connectiondatabase table indicating a plurality of virtual connections to aplurality of client devices directly connected to the other computingdevices. In some examples, a content switcher may receive, from theclient device, a connection request indicating an identifier associatedwith the client device. The content switcher route, based on theidentifier, the connection request to the cluster of computing devices.The establishing the bidirectional connection with the client device maybe based on the connection request.

In some examples, based on the establishing the bidirectional connectionwith the client device, the first computing device may update the clientdevice with information associated with virtual connections to the othercomputing devices. The first computing device may update the othercomputing devices with information associated with a virtual connectionto the client device. In some examples, each of the bidirectionalconnection with the client device and the bidirectional connections withthe other computing devices may comprise one of a WebSocket connection,a HTTP persistent connection, or a Comet connection.

These and additional aspects will be appreciated with the benefit of thedisclosures discussed in further detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of aspects described herein and theadvantages thereof may be acquired by referring to the followingdescription in consideration of the accompanying drawings, in which likereference numbers indicate like features, and wherein:

FIG. 1 depicts an illustrative computer system architecture that may beused in accordance with one or more illustrative aspects describedherein.

FIG. 2 depicts an illustrative remote-access system architecture thatmay be used in accordance with one or more illustrative aspectsdescribed herein.

FIG. 3 depicts an illustrative virtualized (hypervisor) systemarchitecture that may be used in accordance with one or moreillustrative aspects described herein.

FIG. 4 depicts an illustrative cloud-based system architecture that maybe used in accordance with one or more illustrative aspects describedherein.

FIG. 5 is a schematic diagram showing an example system for providingbidirectional communications between client devices and server devices.

FIG. 6 is a schematic diagram showing an example system for configuringvirtual connections.

FIG. 7 is a flowchart showing an example method for configuringbidirectional connections between client devices and server devices.

FIG. 8 is a flowchart showing an example method for configuringbidirectional connections among server devices.

FIG. 9 is a flowchart showing an example method for communicatingbetween client devices and server devices.

FIG. 10 is a flowchart showing an example method for communicatingbetween server devices and client devices.

FIG. 11 is a flowchart showing an example method for providingbidirectional communications between server devices and client devices.

DETAILED DESCRIPTION

In the following description of the various embodiments, reference ismade to the accompanying drawings identified above and which form a parthereof, and in which is shown by way of illustration various embodimentsin which aspects described herein may be practiced. It is to beunderstood that other embodiments may be utilized and structural andfunctional modifications may be made without departing from the scopedescribed herein. Various aspects are capable of other embodiments andof being practiced or being carried out in various different ways.

As a general introduction to the subject matter described in more detailbelow, aspects described herein are directed towards providingbidirectional communications between client devices (e.g., physicalcomputing devices, or virtual machines, configured to host virtualapplications and/or virtual desktops) and server devices (e.g.,configured to implement control plane functions for managing the clientdevices) are described herein. Server devices in a cluster maybidirectionally communicate with client devices in a resource site viadirect connections or virtual connections. Direct connections may beconfigured to deliver messages between server devices and client deviceswithout other server devices acting as intermediaries. Virtualconnections may be configured to deliver messages between server devicesand client devices via other server devices acting as intermediaries.Server devices may distinguish different types of messages (e.g., sentvia direct connections or virtual connections) based on the headercontents of the messages, and may accordingly keep the messages orforward the messages.

To perform various control plane functions for managing the clientdevices in a resource site, each of the server devices in a clustercorresponding to the resource site may be configured to establishbidirectional connections with all of the client devices. The totalnumber of bidirectional connections between the server devices and theclient devices may, for example, correspond to the total number of theserver devices multiplied by the total number of the client devices. Ifthe number of the client devices increases, and the number ofcorresponding server devices increases as well (e.g., to handle theadditional load of the client devices), the total number ofbidirectional connections between the server devices and the clientdevices may become very large, and may contribute to higher consumptionof resources (e.g., networking resources). Additionally oralternatively, the scalability of the system may be impeded (e.g.,networking resources of a server device may impose a limit on the totalnumber of bidirectional connections it may establish).

Configuring virtual connections between server devices and clientdevices may help alleviate these challenges. Each of the client devicesin a resource site may establish a bidirectional connection with oneserver device in the cluster corresponding to the resource site. Theserver devices in the cluster may form a mesh network (e.g.,establishing bidirectional connections with each other). A client devicein the resource site may bidirectionally communicate with a serverdevice in the cluster via a direct connection between the client deviceand the server device. Additionally or alternatively, a client device inthe resource site may bidirectionally communicate with a server devicein the cluster via a virtual connection comprising another serverdevice, in the cluster, acting as an intermediary and configured toforward messages from the client device to the server device or from theserver device to the client device. Configuring a client device with adirect bidirectional connection with one server device in a cluster andvirtual connection(s) with other server device(s) in the cluster mayreduce resource consumption and/or facilitate the scalability of thesystem. For example, a client device might only need to establish abidirectional connection with one server device. Resource consumptionmay be reduced as the total number of bidirectional connections betweenclient devices and server devices may be reduced. The system may be ableto scale as the number of bidirectional connections each server devicehas may be reduced.

It is to be understood that the phraseology and terminology used hereinare for the purpose of description and should not be regarded aslimiting. Rather, the phrases and terms used herein are to be giventheir broadest interpretation and meaning. The use of “including” and“comprising” and variations thereof is meant to encompass the itemslisted thereafter and equivalents thereof as well as additional itemsand equivalents thereof. The use of the terms “connected,” “coupled,”and similar terms, is meant to include both direct and indirectmounting, connecting, coupling, positioning and engaging.

Computing Architecture

Computer software, hardware, and networks may be utilized in a varietyof different system environments, including standalone, networked,remote-access (also known as remote desktop), virtualized, and/orcloud-based environments, among others. FIG. 1 illustrates one exampleof a system architecture and data processing device that may be used toimplement one or more illustrative aspects described herein in astandalone and/or networked environment. Various network nodes 103, 105,107, and 109 may be interconnected via a wide area network (WAN) 101,such as the Internet. Other networks may also or alternatively be used,including private intranets, corporate networks, local area networks(LAN), metropolitan area networks (MAN), wireless networks, personalnetworks (PAN), and the like. Network 101 is for illustration purposesand may be replaced with fewer or additional computer networks. A localarea network 133 may have one or more of any known LAN topology and mayuse one or more of a variety of different protocols, such as Ethernet.Devices 103, 105, 107, and 109 and other devices (not shown) may beconnected to one or more of the networks via twisted pair wires, coaxialcable, fiber optics, radio waves, or other communication media.

The term “network” as used herein and depicted in the drawings refersnot only to systems in which remote storage devices are coupled togethervia one or more communication paths, but also to stand-alone devicesthat may be coupled, from time to time, to such systems that havestorage capability. Consequently, the term “network” includes not only a“physical network” but also a “content network,” which is comprised ofthe data—attributable to a single entity—which resides across allphysical networks.

The components may include data server 103, web server 105, and clientcomputers 107, 109. Data server 103 provides overall access, control andadministration of databases and control software for performing one ormore illustrative aspects describe herein. Data server 103 may beconnected to web server 105 through which users interact with and obtaindata as requested. Alternatively, data server 103 may act as a webserver itself and be directly connected to the Internet. Data server 103may be connected to web server 105 through the local area network 133,the wide area network 101 (e.g., the Internet), via direct or indirectconnection, or via some other network. Users may interact with the dataserver 103 using remote computers 107, 109, e.g., using a web browser toconnect to the data server 103 via one or more externally exposed websites hosted by web server 105. Client computers 107, 109 may be used inconcert with data server 103 to access data stored therein, or may beused for other purposes. For example, from client device 107 a user mayaccess web server 105 using an Internet browser, as is known in the art,or by executing a software application that communicates with web server105 and/or data server 103 over a computer network (such as theInternet).

Servers and applications may be combined on the same physical machines,and retain separate virtual or logical addresses, or may reside onseparate physical machines. FIG. 1 illustrates just one example of anetwork architecture that may be used, and those of skill in the artwill appreciate that the specific network architecture and dataprocessing devices used may vary, and are secondary to the functionalitythat they provide, as further described herein. For example, servicesprovided by web server 105 and data server 103 may be combined on asingle server.

Each component 103, 105, 107, 109 may be any type of known computer,server, or data processing device. Data server 103, e.g., may include aprocessor 111 controlling overall operation of the data server 103. Dataserver 103 may further include random access memory (RAM) 113, read onlymemory (ROM) 115, network interface 117, input/output interfaces 119(e.g., keyboard, mouse, display, printer, etc.), and memory 121.Input/output (I/O) 119 may include a variety of interface units anddrives for reading, writing, displaying, and/or printing data or files.Memory 121 may further store operating system software 123 forcontrolling overall operation of the data processing device 103, controllogic 125 for instructing data server 103 to perform aspects describedherein, and other application software 127 providing secondary, support,and/or other functionality which may or might not be used in conjunctionwith aspects described herein. The control logic 125 may also bereferred to herein as the data server software 125. Functionality of thedata server software 125 may refer to operations or decisions madeautomatically based on rules coded into the control logic 125, mademanually by a user providing input into the system, and/or a combinationof automatic processing based on user input (e.g., queries, dataupdates, etc.).

Memory 121 may also store data used in performance of one or moreaspects described herein, including a first database 129 and a seconddatabase 131. In some embodiments, the first database 129 may includethe second database 131 (e.g., as a separate table, report, etc.). Thatis, the information can be stored in a single database, or separatedinto different logical, virtual, or physical databases, depending onsystem design. Devices 105, 107, and 109 may have similar or differentarchitecture as described with respect to device 103. Those of skill inthe art will appreciate that the functionality of data processing device103 (or device 105, 107, or 109) as described herein may be spreadacross multiple data processing devices, for example, to distributeprocessing load across multiple computers, to segregate transactionsbased on geographic location, user access level, quality of service(QoS), etc.

One or more aspects may be embodied in computer-usable or readable dataand/or computer-executable instructions, such as in one or more programmodules, executed by one or more computers or other devices as describedherein. Generally, program modules include routines, programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types when executed by a processor ina computer or other device. The modules may be written in a source codeprogramming language that is subsequently compiled for execution, or maybe written in a scripting language such as (but not limited to)HyperText Markup Language (HTML) or Extensible Markup Language (XML).The computer executable instructions may be stored on a computerreadable medium such as a nonvolatile storage device. Any suitablecomputer readable storage media may be utilized, including hard disks,CD-ROMs, optical storage devices, magnetic storage devices, and/or anycombination thereof. In addition, various transmission (non-storage)media representing data or events as described herein may be transferredbetween a source and a destination in the form of electromagnetic wavestraveling through signal-conducting media such as metal wires, opticalfibers, and/or wireless transmission media (e.g., air and/or space).Various aspects described herein may be embodied as a method, a dataprocessing system, or a computer program product. Therefore, variousfunctionalities may be embodied in whole or in part in software,firmware, and/or hardware or hardware equivalents such as integratedcircuits, field programmable gate arrays (FPGA), and the like.Particular data structures may be used to more effectively implement oneor more aspects described herein, and such data structures arecontemplated within the scope of computer executable instructions andcomputer-usable data described herein.

With further reference to FIG. 2, one or more aspects described hereinmay be implemented in a remote-access environment. FIG. 2 depicts anexample system architecture including a computing device 201 in anillustrative computing environment 200 that may be used according to oneor more illustrative aspects described herein. Computing device 201 maybe used as a server 206 a in a single-server or multi-server desktopvirtualization system (e.g., a remote access or cloud system) and can beconfigured to provide virtual machines for client access devices. Thecomputing device 201 may have a processor 203 for controlling overalloperation of the device 201 and its associated components, including RAM205, ROM 207, Input/Output (I/O) module 209, and memory 215.

I/O module 209 may include a mouse, keypad, touch screen, scanner,optical reader, and/or stylus (or other input device(s)) through which auser of computing device 201 may provide input, and may also include oneor more of a speaker for providing audio output and one or more of avideo display device for providing textual, audiovisual, and/orgraphical output. Software may be stored within memory 215 and/or otherstorage to provide instructions to processor 203 for configuringcomputing device 201 into a special purpose computing device in order toperform various functions as described herein. For example, memory 215may store software used by the computing device 201, such as anoperating system 217, application programs 219, and an associateddatabase 221.

Computing device 201 may operate in a networked environment supportingconnections to one or more remote computers, such as terminals 240 (alsoreferred to as client devices). The terminals 240 may be personalcomputers, mobile devices, laptop computers, tablets, or servers thatinclude many or all of the elements described above with respect to thecomputing device 103 or 201. The network connections depicted in FIG. 2include a local area network (LAN) 225 and a wide area network (WAN)229, but may also include other networks. When used in a LAN networkingenvironment, computing device 201 may be connected to the LAN 225through a network interface or adapter 223. When used in a WANnetworking environment, computing device 201 may include a modem orother wide area network interface 227 for establishing communicationsover the WAN 229, such as computer network 230 (e.g., the Internet). Itwill be appreciated that the network connections shown are illustrativeand other means of establishing a communications link between thecomputers may be used. Computing device 201 and/or terminals 240 mayalso be mobile terminals (e.g., mobile phones, smartphones, personaldigital assistants (PDAs), notebooks, etc.) including various othercomponents, such as a battery, speaker, and antennas (not shown).

Aspects described herein may also be operational with numerous othergeneral purpose or special purpose computing system environments orconfigurations. Examples of other computing systems, environments,and/or configurations that may be suitable for use with aspectsdescribed herein include, but are not limited to, personal computers,server computers, hand-held or laptop devices, multiprocessor systems,microprocessor-based systems, set top boxes, programmable consumerelectronics, network personal computers (PCs), minicomputers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

As shown in FIG. 2, one or more client devices 240 may be incommunication with one or more servers 206 a-206 n (generally referredto herein as “server(s) 206”). In one embodiment, the computingenvironment 200 may include a network appliance installed between theserver(s) 206 and client machine(s) 240. The network appliance maymanage client/server connections, and in some cases can load balanceclient connections amongst a plurality of backend servers 206.

The client machine(s) 240 may in some embodiments be referred to as asingle client machine 240 or a single group of client machines 240,while server(s) 206 may be referred to as a single server 206 or asingle group of servers 206. In one embodiment a single client machine240 communicates with more than one server 206, while in anotherembodiment a single server 206 communicates with more than one clientmachine 240. In yet another embodiment, a single client machine 240communicates with a single server 206.

A client machine 240 can, in some embodiments, be referenced by any oneof the following non-exhaustive terms: client machine(s); client(s);client computer(s); client device(s); client computing device(s); localmachine; remote machine; client node(s); endpoint(s); or endpointnode(s). The server 206, in some embodiments, may be referenced by anyone of the following non-exhaustive terms: server(s), local machine;remote machine; server farm(s), or host computing device(s).

In one embodiment, the client machine 240 may be a virtual machine. Thevirtual machine may be any virtual machine, while in some embodimentsthe virtual machine may be any virtual machine managed by a Type 1 orType 2 hypervisor, for example, a hypervisor developed by CitrixSystems, IBM, VMware, or any other hypervisor. In some aspects, thevirtual machine may be managed by a hypervisor, while in other aspectsthe virtual machine may be managed by a hypervisor executing on a server206 or a hypervisor executing on a client 240.

Some embodiments include a client device 240 that displays applicationoutput generated by an application remotely executing on a server 206 orother remotely located machine. In these embodiments, the client device240 may execute a virtual machine receiver program or application todisplay the output in an application window, a browser, or other outputwindow. In one example, the application is a desktop, while in otherexamples the application is an application that generates or presents adesktop. A desktop may include a graphical shell providing a userinterface for an instance of an operating system in which local and/orremote applications can be integrated. Applications, as used herein, areprograms that execute after an instance of an operating system (and,optionally, also the desktop) has been loaded.

The server 206, in some embodiments, uses a remote presentation protocolor other program to send data to a thin-client or remote-displayapplication executing on the client to present display output generatedby an application executing on the server 206. The thin-client orremote-display protocol can be any one of the following non-exhaustivelist of protocols: the Independent Computing Architecture (ICA) protocoldeveloped by Citrix Systems, Inc. of Ft. Lauderdale, Fla.; or the RemoteDesktop Protocol (RDP) manufactured by the Microsoft Corporation ofRedmond, Wash.

A remote computing environment may include more than one server 206a-206 n such that the servers 206 a-206 n are logically grouped togetherinto a server farm 206, for example, in a cloud computing environment.The server farm 206 may include servers 206 that are geographicallydispersed while logically grouped together, or servers 206 that arelocated proximate to each other while logically grouped together.Geographically dispersed servers 206 a-206 n within a server farm 206can, in some embodiments, communicate using a WAN (wide), MAN(metropolitan), or LAN (local), where different geographic regions canbe characterized as: different continents; different regions of acontinent; different countries; different states; different cities;different campuses; different rooms; or any combination of the precedinggeographical locations. In some embodiments the server farm 206 may beadministered as a single entity, while in other embodiments the serverfarm 206 can include multiple server farms.

In some embodiments, a server farm may include servers 206 that executea substantially similar type of operating system platform (e.g.,WINDOWS, UNIX, LINUX, iOS, ANDROID, SYMBIAN, etc.) In other embodiments,server farm 206 may include a first group of one or more servers thatexecute a first type of operating system platform, and a second group ofone or more servers that execute a second type of operating systemplatform.

Server 206 may be configured as any type of server, as needed, e.g., afile server, an application server, a web server, a proxy server, anappliance, a network appliance, a gateway, an application gateway, agateway server, a virtualization server, a deployment server, a SecureSockets Layer (SSL) VPN server, a firewall, a web server, an applicationserver or as a master application server, a server executing an activedirectory, or a server executing an application acceleration programthat provides firewall functionality, application functionality, or loadbalancing functionality. Other server types may also be used.

Some embodiments include a first server 206 a that receives requestsfrom a client machine 240, forwards the request to a second server 206 b(not shown), and responds to the request generated by the client machine240 with a response from the second server 206 b (not shown.) Firstserver 206 a may acquire an enumeration of applications available to theclient machine 240 as well as address information associated with anapplication server 206 hosting an application identified within theenumeration of applications. First server 206 a can then present aresponse to the client's request using a web interface, and communicatedirectly with the client 240 to provide the client 240 with access to anidentified application. One or more clients 240 and/or one or moreservers 206 may transmit data over network 230, e.g., network 101.

FIG. 3 shows a high-level architecture of an illustrative desktopvirtualization system. As shown, the desktop virtualization system maybe single-server or multi-server system, or cloud system, including atleast one virtualization server 301 configured to provide virtualdesktops and/or virtual applications to one or more client accessdevices 240. As used herein, a desktop refers to a graphical environmentor space in which one or more applications may be hosted and/orexecuted. A desktop may include a graphical shell providing a userinterface for an instance of an operating system in which local and/orremote applications can be integrated. Applications may include programsthat execute after an instance of an operating system (and, optionally,also the desktop) has been loaded. Each instance of the operating systemmay be physical (e.g., one operating system per device) or virtual(e.g., many instances of an OS running on a single device). Eachapplication may be executed on a local device, or executed on a remotelylocated device (e.g., remoted).

A computer device 301 may be configured as a virtualization server in avirtualization environment, for example, a single-server, multi-server,or cloud computing environment. Virtualization server 301 illustrated inFIG. 3 can be deployed as and/or implemented by one or more embodimentsof the server 206 illustrated in FIG. 2 or by other known computingdevices. Included in virtualization server 301 is a hardware layer thatcan include one or more physical disks 304, one or more physical devices306, one or more physical processors 308, and one or more physicalmemories 316. In some embodiments, firmware 312 can be stored within amemory element in the physical memory 316 and can be executed by one ormore of the physical processors 308. Virtualization server 301 mayfurther include an operating system 314 that may be stored in a memoryelement in the physical memory 316 and executed by one or more of thephysical processors 308. Still further, a hypervisor 302 may be storedin a memory element in the physical memory 316 and can be executed byone or more of the physical processors 308.

Executing on one or more of the physical processors 308 may be one ormore virtual machines 332A-C (generally 332). Each virtual machine 332may have a virtual disk 326A-C and a virtual processor 328A-C. In someembodiments, a first virtual machine 332A may execute, using a virtualprocessor 328A, a control program 320 that includes a tools stack 324.Control program 320 may be referred to as a control virtual machine,Dom0, Domain 0, or other virtual machine used for system administrationand/or control. In some embodiments, one or more virtual machines 332B-Ccan execute, using a virtual processor 328B-C, a guest operating system330A-B.

Virtualization server 301 may include a hardware layer 310 with one ormore pieces of hardware that communicate with the virtualization server301. In some embodiments, the hardware layer 310 can include one or morephysical disks 304, one or more physical devices 306, one or morephysical processors 308, and one or more physical memory 316. Physicalcomponents 304, 306, 308, and 316 may include, for example, any of thecomponents described above. Physical devices 306 may include, forexample, a network interface card, a video card, a keyboard, a mouse, aninput device, a monitor, a display device, speakers, an optical drive, astorage device, a universal serial bus connection, a printer, a scanner,a network element (e.g., router, firewall, network address translator,load balancer, virtual private network (VPN) gateway, Dynamic HostConfiguration Protocol (DHCP) router, etc.), or any device connected toor communicating with virtualization server 301. Physical memory 316 inthe hardware layer 310 may include any type of memory. Physical memory316 may store data, and in some embodiments may store one or moreprograms, or set of executable instructions. FIG. 3 illustrates anembodiment where firmware 312 is stored within the physical memory 316of virtualization server 301. Programs or executable instructions storedin the physical memory 316 can be executed by the one or more processors308 of virtualization server 301.

Virtualization server 301 may also include a hypervisor 302. In someembodiments, hypervisor 302 may be a program executed by processors 308on virtualization server 301 to create and manage any number of virtualmachines 332. Hypervisor 302 may be referred to as a virtual machinemonitor, or platform virtualization software. In some embodiments,hypervisor 302 can be any combination of executable instructions andhardware that monitors virtual machines executing on a computingmachine. Hypervisor 302 may be Type 2 hypervisor, where the hypervisorexecutes within an operating system 314 executing on the virtualizationserver 301. Virtual machines may then execute at a level above thehypervisor 302. In some embodiments, the Type 2 hypervisor may executewithin the context of a user's operating system such that the Type 2hypervisor interacts with the user's operating system. In otherembodiments, one or more virtualization servers 301 in a virtualizationenvironment may instead include a Type 1 hypervisor (not shown). A Type1 hypervisor may execute on the virtualization server 301 by directlyaccessing the hardware and resources within the hardware layer 310. Thatis, while a Type 2 hypervisor 302 accesses system resources through ahost operating system 314, as shown, a Type 1 hypervisor may directlyaccess all system resources without the host operating system 314. AType 1 hypervisor may execute directly on one or more physicalprocessors 308 of virtualization server 301, and may include programdata stored in the physical memory 316.

Hypervisor 302, in some embodiments, can provide virtual resources tooperating systems 330 or control programs 320 executing on virtualmachines 332 in any manner that simulates the operating systems 330 orcontrol programs 320 having direct access to system resources. Systemresources can include, but are not limited to, physical devices 306,physical disks 304, physical processors 308, physical memory 316, andany other component included in hardware layer 310 of the virtualizationserver 301. Hypervisor 302 may be used to emulate virtual hardware,partition physical hardware, virtualize physical hardware, and/orexecute virtual machines that provide access to computing environments.In still other embodiments, hypervisor 302 may control processorscheduling and memory partitioning for a virtual machine 332 executingon virtualization server 301. Hypervisor 302 may include thosemanufactured by VMWare, Inc., of Palo Alto, Calif.; the XENPROJECThypervisor, an open source product whose development is overseen by theopen source XenProject.org community; HyperV, VirtualServer or virtualPC hypervisors provided by Microsoft, or others. In some embodiments,virtualization server 301 may execute a hypervisor 302 that creates avirtual machine platform on which guest operating systems may execute.In these embodiments, the virtualization server 301 may be referred toas a host server. An example of such a virtualization server is theXENSERVER provided by Citrix Systems, Inc., of Fort Lauderdale, Fla.

Hypervisor 302 may create one or more virtual machines 332B-C (generally332) in which guest operating systems 330 execute. In some embodiments,hypervisor 302 may load a virtual machine image to create a virtualmachine 332. In other embodiments, the hypervisor 302 may execute aguest operating system 330 within virtual machine 332. In still otherembodiments, virtual machine 332 may execute guest operating system 330.

In addition to creating virtual machines 332, hypervisor 302 may controlthe execution of at least one virtual machine 332. In other embodiments,hypervisor 302 may present at least one virtual machine 332 with anabstraction of at least one hardware resource provided by thevirtualization server 301 (e.g., any hardware resource available withinthe hardware layer 310). In other embodiments, hypervisor 302 maycontrol the manner in which virtual machines 332 access physicalprocessors 308 available in virtualization server 301. Controllingaccess to physical processors 308 may include determining whether avirtual machine 332 should have access to a processor 308, and howphysical processor capabilities are presented to the virtual machine332.

As shown in FIG. 3, virtualization server 301 may host or execute one ormore virtual machines 332. A virtual machine 332 is a set of executableinstructions that, when executed by a processor 308, may imitate theoperation of a physical computer such that the virtual machine 332 canexecute programs and processes much like a physical computing device.While FIG. 3 illustrates an embodiment where a virtualization server 301hosts three virtual machines 332, in other embodiments virtualizationserver 301 can host any number of virtual machines 332. Hypervisor 302,in some embodiments, may provide each virtual machine 332 with a uniquevirtual view of the physical hardware, memory, processor, and othersystem resources available to that virtual machine 332. In someembodiments, the unique virtual view can be based on one or more ofvirtual machine permissions, application of a policy engine to one ormore virtual machine identifiers, a user accessing a virtual machine,the applications executing on a virtual machine, networks accessed by avirtual machine, or any other desired criteria. For instance, hypervisor302 may create one or more unsecure virtual machines 332 and one or moresecure virtual machines 332. Unsecure virtual machines 332 may beprevented from accessing resources, hardware, memory locations, andprograms that secure virtual machines 332 may be permitted to access. Inother embodiments, hypervisor 302 may provide each virtual machine 332with a substantially similar virtual view of the physical hardware,memory, processor, and other system resources available to the virtualmachines 332.

Each virtual machine 332 may include a virtual disk 326A-C (generally326) and a virtual processor 328A-C (generally 328.) The virtual disk326, in some embodiments, is a virtualized view of one or more physicaldisks 304 of the virtualization server 301, or a portion of one or morephysical disks 304 of the virtualization server 301. The virtualizedview of the physical disks 304 can be generated, provided, and managedby the hypervisor 302. In some embodiments, hypervisor 302 provides eachvirtual machine 332 with a unique view of the physical disks 304. Thus,in these embodiments, the particular virtual disk 326 included in eachvirtual machine 332 can be unique when compared with the other virtualdisks 326.

A virtual processor 328 can be a virtualized view of one or morephysical processors 308 of the virtualization server 301. In someembodiments, the virtualized view of the physical processors 308 can begenerated, provided, and managed by hypervisor 302. In some embodiments,virtual processor 328 has substantially all of the same characteristicsof at least one physical processor 308. In other embodiments, virtualprocessor 308 provides a modified view of physical processors 308 suchthat at least some of the characteristics of the virtual processor 328are different than the characteristics of the corresponding physicalprocessor 308.

With further reference to FIG. 4, some aspects described herein may beimplemented in a cloud-based environment. FIG. 4 illustrates an exampleof a cloud computing environment (or cloud system) 400. As seen in FIG.4, client computers 411-414 may communicate with a cloud managementserver 410 to access the computing resources (e.g., host servers 403a-403 b (generally referred herein as “host servers 403”), storageresources 404 a-404 b (generally referred herein as “storage resources404”), and network elements 405 a-405 b (generally referred herein as“network resources 405”)) of the cloud system.

Management server 410 may be implemented on one or more physicalservers. The management server 410 may run, for example, CLOUDPLATFORMor OPENSTACK, among others. Management server 410 may manage variouscomputing resources, including cloud hardware and software resources,for example, host computers 403, data storage devices 404, andnetworking devices 405. The cloud hardware and software resources mayinclude private and/or public components. For example, a cloud may beconfigured as a private cloud to be used by one or more particularcustomers or client computers 411-414 and/or over a private network. Inother embodiments, public clouds or hybrid public-private clouds may beused by other customers over an open or hybrid networks.

Management server 410 may be configured to provide user interfacesthrough which cloud operators and cloud customers may interact with thecloud system 400. For example, the management server 410 may provide aset of application programming interfaces (APIs) and/or one or morecloud operator console applications (e.g., web-based or standaloneapplications) with user interfaces to allow cloud operators to managethe cloud resources, configure the virtualization layer, manage customeraccounts, and perform other cloud administration tasks. The managementserver 410 also may include a set of APIs and/or one or more customerconsole applications with user interfaces configured to receive cloudcomputing requests from end users via client computers 411-414, forexample, requests to create, modify, or destroy virtual machines withinthe cloud. Client computers 411-414 may connect to management server 410via the Internet or some other communication network, and may requestaccess to one or more of the computing resources managed by managementserver 410. In response to client requests, the management server 410may include a resource manager configured to select and provisionphysical resources in the hardware layer of the cloud system based onthe client requests. For example, the management server 410 andadditional components of the cloud system may be configured toprovision, create, and manage virtual machines and their operatingenvironments (e.g., hypervisors, storage resources, services offered bythe network elements, etc.) for customers at client computers 411-414,over a network (e.g., the Internet), providing customers withcomputational resources, data storage services, networking capabilities,and computer platform and application support. Cloud systems also may beconfigured to provide various specific services, including securitysystems, development environments, user interfaces, and the like.

Certain clients 411-414 may be related, for example, to different clientcomputers creating virtual machines on behalf of the same end user, ordifferent users affiliated with the same company or organization. Inother examples, certain clients 411-414 may be unrelated, such as usersaffiliated with different companies or organizations. For unrelatedclients, information on the virtual machines or storage of any one usermay be hidden from other users.

Referring now to the physical hardware layer of a cloud computingenvironment, availability zones 401-402 (or zones) may refer to acollocated set of physical computing resources. Zones may begeographically separated from other zones in the overall cloud ofcomputing resources. For example, zone 401 may be a first clouddatacenter located in California, and zone 402 may be a second clouddatacenter located in Florida. Management server 410 may be located atone of the availability zones, or at a separate location. Each zone mayinclude an internal network that interfaces with devices that areoutside of the zone, such as the management server 410, through agateway. End users of the cloud (e.g., clients 411-414) might or mightnot be aware of the distinctions between zones. For example, an end usermay request the creation of a virtual machine having a specified amountof memory, processing power, and network capabilities. The managementserver 410 may respond to the user's request and may allocate theresources to create the virtual machine without the user knowing whetherthe virtual machine was created using resources from zone 401 or zone402. In other examples, the cloud system may allow end users to requestthat virtual machines (or other cloud resources) are allocated in aspecific zone or on specific resources 403-405 within a zone.

In this example, each zone 401-402 may include an arrangement of variousphysical hardware components (or computing resources) 403-405, forexample, physical hosting resources (or processing resources), physicalnetwork resources, physical storage resources, switches, and additionalhardware resources that may be used to provide cloud computing servicesto customers. The physical hosting resources in a cloud zone 401-402 mayinclude one or more computer servers 403, such as the virtualizationservers 301 described above, which may be configured to create and hostvirtual machine instances. The physical network resources in a cloudzone 401 or 402 may include one or more network elements 405 (e.g.,network service providers) comprising hardware and/or softwareconfigured to provide a network service to cloud customers, such asfirewalls, network address translators, load balancers, virtual privatenetwork (VPN) gateways, Dynamic Host Configuration Protocol (DHCP)routers, and the like. The storage resources in the cloud zone 401-402may include storage disks (e.g., solid state drives (SSDs), magnetichard disks, etc.) and other storage devices.

The example cloud computing environment shown in FIG. 4 also may includea virtualization layer (e.g., as shown in FIGS. 1-3) with additionalhardware and/or software resources configured to create and managevirtual machines and provide other services to customers using thephysical resources in the cloud. The virtualization layer may includehypervisors, as described above in FIG. 3, along with other componentsto provide network virtualizations, storage virtualizations, etc. Thevirtualization layer may be as a separate layer from the physicalresource layer, or may share some or all of the same hardware and/orsoftware resources with the physical resource layer. For example, thevirtualization layer may include a hypervisor installed in each of thevirtualization servers 403 with the physical computing resources. Knowncloud systems may alternatively be used, e.g., WINDOWS AZURE (MicrosoftCorporation of Redmond Wash.), AMAZON EC2 (Amazon.com Inc. of Seattle,Wash.), IBM BLUE CLOUD (IBM Corporation of Armonk, N.Y.), or others.

Bidirectional Communication Clusters

FIG. 5 is a schematic diagram showing an example system for providingbidirectional communications between client devices and server devices.The system may include one or more user devices (e.g., user devices501A, 501B), one or more networks (e.g., network 503), one or more cloudservices (e.g., cloud service 505), and one or more resource sites(e.g., resource sites 507A, 507B). The user devices 501A, 501B mayinclude, for example, a smartphone, personal computer, tablet, desktopcomputer, laptop computer, gaming device, virtual reality headset, orany other computing device having an interface to communicate with thenetwork 503. Additionally, the user devices 501A, 501B may include, forexample, the computers 107, 109, the terminals 240, or the clientcomputers 411-414 as discussed above in connection with FIGS. 1, 2, and4.

The network 503 may include one or more of any of various types ofinformation distribution networks, such as, without limitation, asatellite network, a telephone network, a cellular network, a Wi-Finetwork, an Ethernet network, an optical fiber network, a coaxial cablenetwork, a hybrid fiber coax network, etc. The network 503 may includean Internet Protocol (IP) based network (e.g., the Internet) or othertypes of networks. The network 503 may include, for example, the widearea network 101, the local area network 133, or the computer network230. The network 503 may use a plurality of interconnected communicationlinks to connect the user devices 501A, 501B, the cloud service 505, andthe resource sites 507A, 507B. For example, the user devices 501A, 501Bmay access, via the network 503, the cloud service 505 and the resourcesites 507A, 507B.

The cloud service 505 and the resource sites 507A, 507B may provideservices (e.g., virtual applications, virtual desktops, etc.) to theuser devices 501A, 501B. For example, the cloud service 505 and theresource sites 507A, 507B may implement application virtualizationsoftware and/or desktop virtualization software for providing virtualapplications and/or virtual desktops. The resource sites 507A, 507B maycomprise, for example, locations of computing resources for hostingvirtual applications and/or virtual desktops to be provided to users.Each of the resource sites 507A, 507B may include one or more clientdevices, which may be configured to host virtual applications and/orvirtual desktops. For example, the resource site 507A may include clientdevices 521P-521S. There may be additional or alternative client devicesin the resource sites 507A, 507B. The client devices 521P-521S maycomprise a physical computing device (e.g., the data server 103, the webserver 105, the server 206, etc.). Additionally or alternatively, theclient devices 521P-521S may comprise a virtual machine. For example,the resource site 507A may include the virtualization server 301, andthe client devices 521P-521S may include the virtual machines 332A-332C.

The resource sites (e.g., the resource sites 507A, 507B) may beassociated with various user groups (e.g., customers of the cloudservice 505). For example, a customer of the cloud service 505 may havea resource site (e.g., the resource site 507A or 507B) includingphysical computing devices located on the customer's premises. Asanother example, a customer of the cloud service 505 may rent virtualmachines from a cloud vendor, and may organize the virtual machines intoa resource site (e.g., the resource site 507A or 507B) on the cloudvendor's cloud. The client devices in a resource site may be connectedto the network 503. For example, for security purposes and/or otherpurposes, the client devices 521P-521S may communicate with the network503 (e.g., the public Internet) via a gateway (e.g., gateway 523). Thegateway 523 may comprise, for example, any type of computing deviceconfigured to filter traffic coming into the private network, and/or mayshield the client devices 521P-521S from malicious traffic from thepublic Internet. In addition, the client devices 521P-521S maycommunicate with each other via a private network of the resource site507A.

The resource sites (e.g., the resource sites 507A, 507B) may beassociated with various user groups (e.g., customers of the cloudservice 505). A user group may include one or more users, which mayaccess (e.g., via their user devices) virtual applications and/orvirtual desktops running on the client devices in the user group'sresource site. For example, a user group (e.g., a private organization)may have the resource site 507A on-premises, and a user (e.g., anemployee) of the user group may use the user device 501A to accessvirtual applications and/or virtual desktops running on the clientdevices 521P-521S in resource site 507A.

The cloud service 505 may implement one or more control plane functionsfor managing client devices in resource sites. For example, the cloudservice 505 may receive, from user devices (e.g., the user devices 501A,501B), requests to access virtual applications and/or virtual desktopsof the resource sites 507A, 507B. In turn, the cloud service 505 mayassign the requests to client devices in resource sites, and mayfacilitate the user devices to connect to the requested virtualapplications and/or virtual desktops running on the client devices. Asanother example, the cloud service 505 may monitor the running status(e.g., Central Processing Unit (CPU) usage rate, memory usage rate,etc.) of client devices in resource sites, and may provide the monitoredinformation to the user groups (e.g., customers) associated with theresource sites (e.g., to the administrators of the user groups).

The cloud service 505 may include one or more load balancers (e.g., loadbalancer 509), one or more content switchers (e.g., content switcher511), and one or more clusters (e.g., clusters 513, 517). The clusters513, 517 may include one or more server devices. For example, thecluster 513 may include server devices 515A-515C, and the cluster 517may include server devices 519A-519C. There may be additional oralternative server devices in the clusters 513, 517. The control planefunctions for managing client devices in resource sites may beimplemented on the server devices 515A-515C, 519A-519C. The serverdevices 515A-515C, 519A-519C may include a physical computing device ora virtual machine. In some examples, the server devices 515A-515C,519A-519C may be located at different geographical regions to provide adistributed architecture for the clusters 513, 517. For example, thecloud service 505 may comprise one or more hypervisors, which mayautomatically provision in the clusters or remove from the clustersvirtual machines as server devices based on the load on, and thecapacity of, the server devices.

To manage the resource sites 507A, 507B corresponding to various usergroups, the server devices in the cloud service 505 may be organizedinto clusters (e.g., the cluster 513, 517). Each cluster 513, 517 mayhave one or more server devices. One or more user groups may be assignedto a cluster (e.g., such that the cluster may be responsible forhandling incoming messages associated with the one or more user groups).The load balancer 509 and the content switcher 511 may be configured toroute incoming messages (e.g., from the user devices 501A, 501B or theresources sites 507A, 507B) to the corresponding clusters. The contentswitcher 511 may comprise one or more content switches (e.g.,implemented on one or more computing devices). The load balancer 509 maybalance the load of incoming messages among the content switches. Forexample, the load balancer 509 may route incoming messages to thecontent switches in such a manner that the content switches may beevenly used. The content switches may route the messages to theircorresponding clusters based on the user group information of themessages (e.g., as indicated in the headers of the messages). Forexample, a content switch may route a message generated by a user deviceused by a user of a particular user group to a cluster to which theparticular user group is assigned.

The server devices in a cluster may communicate with the client devicesin the resource site(s) corresponding to the cluster to manage theclient devices (e.g., assigning user requests to access virtualapplications to the client devices, gathering running status data of theclient devices, etc.). Bidirectional connections may be used to improvethe performance of communications between client devices and serverdevices (e.g., when the client devices are located within a privatenetwork). A bidirectional connection may comprise any type ofcommunication link configured to allow devices connected thereby tocommunicate bidirectionally. A bidirectional connection may include, forexample, a WebSocket connection, a HTTP persistent connection, a Cometconnection, or any other type of connection providing a full-duplexinteractive communication session between a client and a server. Abidirectional connection may, for example, enable a server device tosend (e.g., push) data to a client device without the client devicefirst sending a request for the data.

For example, if the client device 521P is located within a privatenetwork of the resource site 507A, and a bidirectional connection is notestablished between the client device 521P and a server device in acorresponding cluster, the server device might not be able to send datato the client device 521P if the client device 521P does not first senda request for the data. For example, the gateway 523 may filter out anytraffic initiated by a computing device outside of the private networkand/or not requested by a client device within the private network(e.g., for security purposes and/or other purposes). By establishing abidirectional connection (e.g., a WebSocket connection) between theclient device 521P and the server device, the server device may be ableto push data (e.g., associated with assigning a user request to access avirtual application and/or virtual desktop, requesting running statusdata from the client device 521P, etc.) to the client device 521Pwithout the client device 521P first sending a request for the data.

FIG. 6 is a schematic diagram showing an example system for configuringvirtual connections. The example system may include the cluster 513(including the server devices 515A-515C) and the resource site 507A(including the client devices 521P-521S). The server devices 515A-515Cmay form a mesh network. For example, the server devices 515A-515C mayestablish bidirectional connections with each other (e.g., as indicatedby communication links AB, AC, BC). Additionally or alternatively, theserver devices 515A-515C may be connected with each other (e.g., usingdedicated network adapters) in the server devices 515A-515C, and/or mayform the mesh network on a separate subnet, for increased performance.For example, each of the server devices 515A-515C may have a dedicatednetwork adapter (e.g., a physical network adapter or a virtual networkadapter) for communicating with each other, and may use a separatenetwork adapter for communicating with devices outside of the cluster513 (e.g., the client devices 521P-521S), so that traffic to or from thedevices outside the cluster 513 might not take the resources of thededicated network adapters for internal cluster communications.

Each of the client devices 521P-521S may establish a bidirectionalconnection (e.g., a WebSocket connection) with one of the server devices515A-515C. For example, the client device 521P may establish abidirectional connection with the server device 515A (as indicated by acommunication link PA). The client device 521Q may establish abidirectional connection with the server device 515A (as indicated by acommunication link QA). The client device 521R may establish abidirectional connection with the server device 515C (as indicated by acommunication link RC). The client device 521S may establish abidirectional connection with the server device 515C (as indicated by acommunication link SC). The client devices 521P-521S may communicatewith the server devices 515A-515C via the direct connections. Forexample, the client device 521P may communicate with the server device515A via the communication link PA. Each of the client devices 521P-521Sand/or the server devices 515A-515C may store a connection databasetable configured to store its direct connections with other devices. Theconnection database table may comprise any type of desired storagesystem, such as an ORACLE Database, MySQL, MICROSOFT SQL Server, IBMDB2, etc. For example, a record for a direct connection in a connectiondatabase table of a first device (e.g., a server device or a clientdevice) may include a name data field and a connection data field. Thename data field may store an identifier of a second device (e.g., aserver device or a client device) directly connected to the firstdevice. The connection data field may store an identifier of theconnection between the first device and the second device.

Additionally, the client devices 521P-521S and the server devices515A-515C may create virtual connections with each other, so that afirst device may communicate with a second device not directly connectedto the first device. For example, the client device 521P may create avirtual connection, with the server device 515B, that includes theserver device 515A acting as an intermediate (e.g., gateway) serverdevice. The virtual connection may comprise, for example, a combinationof the bidirectional connection PA and the bidirectional connection AB.The server device 515A may be directly connected to the client device521P, and may be directly connected to the server device 515B. Theserver device 515A may forward messages from the client device 521P tothe server device 515B. The client device 521P may create, in itsconnection database table, a record indicating the virtual connection tothe server device 515B. For example, the record for a virtual connectionmay include a name data field, a gateway connection data field, and adestination connection data field. The name data field may store anidentifier of the virtually connected device. The gateway connectiondata field may store an identifier of the connection between the sourcedevice and the intermediate server device. The destination connectiondata field may store an identifier of the connection between theintermediate server device and the virtually connected device. In someexamples, the destination connection data field of a record, for avirtual connection, stored by a device (e.g., a server device or clientdevice) may be used by the device to identify the virtual connection. Asshown in FIG. 6, the client devices 521P-521S and the server devices515A-515C may store one or more virtual connection records. More detailsregarding generating and/or storing the virtual connection records arefurther discussed in connection with FIGS. 7-8.

A mesh network may be formed among server devices in a cluster (e.g.,the server devices 515A-515C). As an example, in the mesh network (e.g.,a fully mesh network or a fully connected network), each server devicemay be connected to each of the other server devices. A client devicemight only need to connect to one of the server devices in a cluster, tocommunicate with all of the server devices. The one server device mayreceive messages directed to itself from the client device. The oneserver device may also receive messages directed to the other serverdevices from the client device, and may forward the messages to theother server devices via one additional hop. This network arrangementmay facilitate greater efficiency, scalability, and flow of informationfor the system. Additionally or alternatively, server devices in acluster (e.g., the server devices 515A-515C) may form a partial meshnetwork, a star network, a tree network, a ring network, a line network,or any other desired network topology. A client device may communicatewith its directly connected server device, and may communicate withanother server device in the cluster via one or more server devicesacting as intermediaries.

If a source device (e.g., a client device of the client devices521P-521S or a server device of the server devices 515A-515C) sends amessage to a destination device (e.g., a server device of the serverdevices 515A-515C or a client device of the client devices 521P-521S),the source device may determine whether the destination device isdirectly connected to the source device or virtually connected to thesource device, and may configure the message to be sent accordingly. Forexample, if the client device 521P is to send a message to the serverdevice 515A, the client device 521P may determine that the server device515A is directly connected to the client device 521P (e.g., based on aconnection database table of the client device 521P). For example, theconnection database table of the client device 521P may indicate a listof devices connected to it and whether their corresponding connectionsare direct or virtual connections. The client device 521P may send themessage to the server device 515A via that direct connection.

If the client device 521P is to send a message to the server device515B, the client device 521P may determine that the server device 515Bis not directly connected to the client device 521P (e.g., based on theconnection database table of the client device 521P). The client device521P may search its connection database table for the virtual connectionrecord associated with the server device 515B, may update the message toindicate that the message is to be forwarded by an intermediate serverdevice (e.g., the server device 515A) to the server device 515B, and maysend the message to the intermediate server device for forwarding to theserver device 515B. More details regarding communications between clientdevices and server devices are further discussed in connection withFIGS. 9-10.

FIG. 7 is a flowchart showing an example method for configuringbidirectional connections between client devices and server devices. Theexample method may be performed, for example, by the system as describedin connection with FIGS. 5-6. The steps of the example method aredescribed as being performed by particular computing devices for thesake of simplicity, but the steps may be performed by any othercomputing device.

In step 701, a computing device (e.g., the load balancer 509) maydetermine whether a request to establish a bidirectional connection isreceived from a client device (e.g., the client device 521P). Theconnection request may include, for example, a WebSocket handshakerequest, a HTTP persistent connection request, a Comet connectionrequest, or other types of bidirectional connection requests. A clientdevice may send a connection request to the cloud service 505, forexample, if the client device comes online (e.g., the client device ispowered on, provisioned by a hypervisor, etc.). The connection requestmay, for example, indicate the Uniform Resource Identifier (URI) of thecloud service 505.

If a connection request is received from a client device (step 701: Y),the method may proceed to step 703. In step 703, the computing devicemay determine a cluster of server devices and/or a particular serverdevice in the cluster to which to assign the connection request. Forexample, the load balancer 509 may receive the connection request, andmay forward the connection request to a content switch (e.g., running ona particular server) of the content switcher 511. The load balancer 509may choose the content switch to which to forward the connection requestin such a manner that the load of incoming messages may be evenlydistributed among the content switches of the content switcher 511.

A content switch may receive the connection request, and may route theconnection request to a server device in a cluster based on the usergroup information indicated in the connection request. For example, whensending the connection request, the client device may include, in theheader of the connection request, an identifier of the user groupassociated with the client device. The content switch may receive theconnection request, and may inspect the header of the connection requestto determine the user group identifier. The content switch maydetermine, based on the user group identifier, a cluster of serverdevices that are responsible for the user group. For example, thecontent switch may store a mapping of user group identifier to servercluster, and may determine, based on the mapping, the cluster forsending the connection request. The content switch may send theconnection request to the determined cluster.

Additionally, the content switch may select, from the determinedcluster, a server device to which to send the connection request. Thecontent switch may select a server device in such a manner thatconnection requests routed to the cluster may be evenly distributedamong the server devices in the cluster. For example, the content switchmay use a round-robin algorithm to select the server device. The contentswitch may order the server devices, and may put the ordered serverdevices in a circular list. The content switch may sequentially select,from the circular list, server devices for assigning connectionrequests. Additionally or alternatively, the content switch may select aserver device in such a manner that the server devices in the clustermay have substantially similar numbers of direct connections with clientdevices. For example, the content switch may monitor the number ofdirect connections that each of the server devices in the cluster mayhave with client devices, and may select a server device that may have asmaller or same number of direct connections as compared to other serverdevices in the cluster.

In step 705, the computing device (e.g., the content switch) may routethe connection request to the selected server device in the determinedcluster. The server device may receive the connection request, and mayprocess the connection request. In step 707, the server device mayrespond to the connection request. For example, the server device mayaccept the connection request, and may establish a bidirectionalconnection with the client device. The server device may generate anidentifier for the established bidirectional connection (e.g., based onthe connection request). The identifier may include a globally uniqueidentifier (GUID). The server device may send, to the client device, aresponse indicating that the bidirectional connection has beenestablished (e.g., a WebSocket handshake response). The response mayalso indicate the identifier of the established bidirectionalconnection. Additionally, the server device may update its connectiondatabase table to indicate the established bidirectional connection. Forexample, the server device may create a record in its connectiondatabase table to indicate that the client device is directly connectedto the server device.

In step 709, the server device may send, to other server devices in thecluster, messages indicating the established bidirectional connection.For example, the server device may inform the other server devices ofthe identifier of the established bidirectional connection, theidentifier of the server device, and/or the identifier of the clientdevice. The other server devices that receive the information may usethe information to create virtual connections to the client device. Forexample, one of the other server devices may create, in its connectiondatabase table, a new record indicating the virtual connection to theclient device. The name data field of the new record may indicate theidentifier of the client device. The gateway connection data field ofthe new record may indicate the identifier of the bidirectionalconnection between the server device and the one of the other serverdevices. The destination connection data field of the new record mayindicate the identifier of the established bidirectional connectionbetween the server device and the client device. The one of the otherserver devices may use the virtual connection to communicate with theclient device.

In step 711, the server device may send, to the client device, one ormore messages indicating the existing bidirectional connections betweenthe server device and other server devices in the cluster. For example,the server device may inform the client device of the identifiers of theexisting bidirectional connections between the server device and theother server devices, the identifier of the server device, and/or theidentifiers of the other server devices corresponding to the existingbidirectional connections. The client device may use the information togenerate virtual connections to the other server devices in the cluster,in a similar manner as discussed in connection with step 709.

If a connection request is not received from a client device (step 701:N), the method may proceed to step 715. In step 715, a server device(e.g., the server device 515A) may determine whether a request toterminate a bidirectional connection with a client device is received.The connection termination request may be received from a client device(e.g., if the client device comes offline, is powered off, etc.) or fromanother computing device (e.g., a computing device that manages thepower of client devices). Additionally or alternatively, the serverdevice may generate an instruction to terminate a bidirectionalconnection with a client device, for example, if the server device doesnot have enough resources to support the bidirectional connection.

If a connection termination request is not received (step 715: N), themethod may go back to step 701. Otherwise (step 715: Y), the method mayproceed to step 717. In step 717, the server device may terminate thebidirectional connection with the client device. For example, the serverdevice may send, to the client device, a message indicating thetermination of the bidirectional connection. The server device (and/orthe client device) may release resources (e.g., computing resources,networking resources such as the underlying Transmission ControlProtocol (TCP) connection for a WebSocket connection, etc.) used for thebidirectional connection. The server device (and/or the client device)may update its connection database table for the termination (e.g.,removing records associated with the terminated connection from itsconnection database table).

In step 719, the server device may send, to other server devices in thecluster, messages indicating the terminated connection. The other serverdevices may receive the information, and may update their connectiondatabase tables accordingly. For example, one of the other serverdevices may remove, from its connection database table, a recordassociated with the terminated connection. The other server devicesmight not attempt to communicate with the client device via virtualconnections if the bidirectional connection between the server deviceand the client device is terminated.

FIG. 8 is a flowchart showing an example method for configuringbidirectional connections among server devices. The example method maybe performed, for example, by the system as described in connection withFIGS. 5-6. The steps of the example method are described as beingperformed by particular computing devices for the sake of simplicity,but the steps may be performed by any other computing device.

In step 801, a determination may be made (e.g., by the cloud service505) whether a new server device comes online in a cluster (e.g.,powered on, connected to the cluster network, etc.). For example,hypervisors of the cloud service 505 may provision new virtual machinesas server devices in a cluster (e.g., to satisfy the load of thecluster). As another example, the cloud service 505 may be configured topower on a physical computing device as a server device in a cluster(e.g., to satisfy the load of the cluster).

If a new server device comes online in a cluster (step 801: Y), themethod may proceed to step 803. In step 803, the new server device mayestablish communication links (e.g., bidirectional connections) withother server devices in the cluster. As an example, the new serverdevice may establish a bidirectional connection with each of the otherserver devices in the cluster, so that a mesh network may be formedamong the server devices. For example, in the mesh network, each serverdevice may be connected to each of the other server devices. In order tocommunicate with all of the server devices in a cluster, a client devicemight only need to connect to one of the server devices. The one serverdevice may receive messages directed to itself from the client device.The one server device may also receive messages directed to the otherserver devices from the client device, and forward the messages to theother server devices via one additional hop. This network arrangementmay facilitate greater efficiency, scalability, and flow of informationfor the system.

For example, when a server device comes online in a cluster, it may beassigned an identifier (e.g., by the cloud service 505). For example,the new server device may be assigned a random value as its identifier.Additionally or alternatively, a list of server device identifiers maybe maintained, and an available identifier from the list may be assignedto the new server device.

The new server device may receive a list of server device identifierscorresponding to other running server devices in the cluster. The newserver device, as a client, may connect to the other server devices inthe cluster whose identifiers have lower (or higher) values than the newserver device's identifier. For example, the new server device may send,to these server devices with lower (or higher) identifier values,WebSocket handshake requests. These server devices may accept theWebSocket handshake requests, and may respond with WebSocket handshakeresponses.

The new server device, as a server, may connect to the other serverdevices in the cluster whose identifiers have higher (or lower) valuesthan the new server device's identifier. For example, these serverdevices with higher (or lower) identifier values may send, to the newserver device, WebSocket handshake requests within a period of timeafter the new server comes online. Additionally or alternatively, thenew server device may send notifications to these server devices. Forexample, the new server device may send, to these server devices,WebSocket handshake requests (as notifications). These server devicesmay receive the WebSocket handshake requests, and may return rejectionsto the new server device. These server devices, as clients, may thensend, to the new server device, WebSocket handshake requests toestablish bidirectional connections with the new server device. Theserver devices in the cluster may follow the example steps discussedabove to form a network (e.g., a mesh network). The cluster mayautomatically perform the self-maintenance as server devices are broughtup and/or taken down (e.g., so that the network arrangement may bemaintained for features described herein).

In step 805, the server devices in the cluster may send, to the clientdevices connected to the cluster, messages indicating the establishedconnections between the new server device and the other server devices.The client devices may use the information to generate virtualconnections to the new server device in the cluster, in a similar manneras discussed in connection with step 709. In step 807, the other serverdevices in the cluster may send, to the new server device, messagesindicating the connections between the other server devices and theclient devices. The new server device may use the information togenerate virtual connections to the client devices, in a similar manneras discussed in connection with step 709.

If there is no new server device coming online in a cluster (step 801:N), the method may proceed to step 809. In step 809, a determination maybe made whether a running server device in a cluster comes offline. Ifthere is no running server device coming offline in a cluster (step 809:N), the method may go back to step 801. If a running server device comesoffline (step 809: Y), the method may proceed to step 811. In step 811,connections between the server device coming offline and other serverdevices in the cluster may be terminated. For example, when a serverdevice comes offline, the server device may send, to the other serverdevices in the cluster, requests to terminate the connections betweenthe server device and the other server devices. Each of the other serverdevices may mark as terminated its connection with the server devicecoming offline. For example, each of the other server devices mayremove, from the list of active connections in its connection databasetable, its connection with the server device coming offline.Additionally or alternatively, each of the other server devices mayremove, from its connection database table, records of virtualconnections associated with the server device coming offline (e.g.,virtual connections to client devices directly connected to the serverdevice coming offline).

In step 813, each of the other server devices in the cluster may send,to the client devices directly connected to it, messages indicating thatits connection with the server device coming offline has beenterminated. The client devices may receive the messages, and may adjusttheir connection database tables accordingly. For example, the clientdevices may remove, from their connection database tables, the virtualconnections to the server device coming offline.

FIG. 9 is a flowchart showing an example method for communicatingbetween client devices and server devices. The example method may beperformed, for example, by the system as described in connection withFIGS. 5-6. The steps of the example method are described as beingperformed by particular computing devices for the sake of simplicity,but the steps may be performed by any other computing device.

In step 901, a client device (e.g., the client device 521P) maydetermine a server device, in the cluster associated with the clientdevice (e.g., the cluster 513), as the destination to which to send oneor more messages. For example, the client device may determine to send(e.g., periodically) running status data (e.g., the client device'scurrent CPU usage rate, memory usage rate, etc.) to a particular serverdevice (e.g., a server device configured to gather running status dataand to provide the data to users) in the cluster. In step 903, theclient device may determine whether the destination server device isdirectly connected to the client device. For example, the client devicemay have sent to the cloud service 505 a connection request, and mayhave established a direct connection with a server device in the clusterto which the client device is assigned. The client device may store arecord of the direct connection in its connection database table.Additionally or alternatively, after the client device establishes thedirect connection with the server device, the client device may receive,from the server device, messages indicating connections between theserver device and other server devices in the cluster. The client devicemay generate, based on the messages, virtual connections with the otherserver devices, and may store, in its connection database table, recordsof the virtual connections (e.g., in a similar manner as discussed inconnection with step 711 of FIG. 7).

If the destination server device is directly connected to the clientdevice (step 903: Y), the method may proceed to step 907. In step 907,the client device may send, to the destination server device and via thedirect connection between the client device and the destination serverdevice, one or more messages (e.g., messages indicating running statusdata). The one or more messages might not include a forwarding flag datafield and/or a destination connection data field. Additionally oralternatively, the one or more messages may include a forwarding flagdata field (e.g., indicating a non-forwarding flag) and a destinationconnection data field (e.g., indicating an identifier of the directconnection). If the destination server device is not directly connectedto the client device (step 903: N), the method may proceed to step 905.In step 905, the client device may set the forwarding flag anddestination connection identifier for the message to be sent to thedestination server device. The message may include or may be updated toinclude a forwarding flag data field and a destination connection datafield. The forwarding flag data field may be used to indicate that thedevice receiving the message may forward the message. The destinationconnection data field may be used to indicate the connection via whichthe device receiving the message may forward the message.

The client device may configure the forwarding flag data field of themessage with a forwarding flag. The client device may search itsconnection database table to determine the virtual connection to thedestination server device, and may determine the identifier of theconnection between the server device directly connected to the clientdevice and the destination server device. The client device mayconfigure the destination connection data field of the message with theidentifier of the connection. In step 907, the client device may sendthe message to the server device directly connected to the clientdevice. In this situation, the server device directly connected to theclient device may act as an intermediate server device configured toforward the message to the destination server device.

In step 909, the server device that is directly connected to the clientdevice may receive the message from the client device. In step 911, thedirectly connected server device may determine whether the receivedmessage indicates a forwarding flag (e.g., based on the forwarding flagdata field of the message). If the received message does not indicate aforwarding flag (and/or if the message indicates a non-forwarding flag)(step 911: N), the method may proceed to step 915. In step 915, thedirectly connected server device may further process the receivedmessage. For example, the directly connected server device may executeinstructions indicated in the message, may store information indicatedin the message (e.g., the payload of the message) in the directlyconnected server device, etc. The directly connected server device maydetermine that the message was originated from a client device directlyconnected to it (e.g., based on determining that the message does notinclude a destination connection data field, based on determining that adestination connection data field of the message indicates a directconnection of the directly connected server device, etc.). The directlyconnected server device may determine the identity of the client devicefrom which the message was originated, for example, by identifying adirect connection record, in the connection database table of thedirectly connected server device, whose connection data field indicatesthe direct connection identifier (e.g., as indicated in the message).The directly connected server device may use the identity of the clientdevice for future communications (e.g., associated with the message).

If the received message indicates a forwarding flag (step 911: Y), themethod may proceed to step 913. In step 913, the directly connectedserver device may unset the forwarding flag of the message. For example,the directly connected server device may update the forwarding flag datafield of the message with a non-forwarding flag, or may remove theforwarding flag data field from the header of the message. The directlyconnected server device may extract (e.g., read, parse, etc.) thedestination connection identifier from the message, and may override thedestination connection identifier in the message with an originconnection identifier. The origin connection identifier may comprise anidentifier of the connection between the client device and the directlyconnected server device.

In step 917, the directly connected server device may send the messageto the destination server device based on the extracted destinationconnection identifier. In some examples, the forwarding of the messagemight not involve the directly connected server device inspecting orparsing the payload of the message. The computing overhead generated bythe forwarding mechanism may be reduced to inspecting and/or updatingthe header content of the message. The destination server device mayreceive the message, and may inspect the header content of the message.The header content of the message may indicate that the message is notto be forwarded by the destination server device, and may indicate theorigin connection identifier. The destination server device maydetermine that the message was sent via a virtual connection (e.g.,based on determining that the origin connection identifier does notcorrespond to a direct connection of the destination server device). Thedestination server device may determine, based on the origin connectionidentifier, the virtual connection via which the message was sent,and/or the identity of the client device from which the message wasoriginated (e.g., by identifying a virtual connection record, in theconnection database table of the destination server device, whosedestination connection data field indicates the origin connectionidentifier). The destination server device may use the identity of theclient device for future communications (e.g., associated with themessage).

FIG. 10 is a flowchart showing an example method for communicatingbetween server devices and client devices. The example method may beperformed, for example, by the system as described in connection withFIGS. 5-6. The steps of the example method are described as beingperformed by particular computing devices for the sake of simplicity,but the steps may be performed by any other computing device.

In step 1001, a first server device (e.g., the server device 515A) maydetermine a client device to which to send a message. For example, thefirst server device may send, to a particular client device, a remoteprocedure call (RPC) message. As another example, the first serverdevice may send, to a particular client device, a request for runningstatus data of the client device.

In step 1003, the first server device may determine whether the clientdevice is directly connected to the first server device. For example,the first server device may store a list of client devices that aredirectly connected to the first server device, and may determine whetherthe client device as determined in step 1001 is included in the list. Ifthe client device is directly connected to the first server device (step1003: Y), the method may proceed to step 1007. In step 1007, the firstserver device may send the message to the client device via the directconnection between the first server device and the client device. Forexample, the first server device may send, to the client device and viathe direct connection, a request for running status data of the clientdevice. The message might not include a forwarding flag data fieldand/or a destination connection data field. Additionally oralternatively, the message may include a forwarding flag data field(e.g., indicating a non-forwarding flag) and a destination connectiondata field (e.g., indicating an identifier of the direct connection).

In step 1017, the client device may receive the message. The clientdevice may determine that the message is not to be forwarded by theclient device (e.g., based on determining that the message does notinclude a forwarding flag data field, or based on determining that themessage indicates a non-forwarding flag). The client device maydetermine that the message was originated from a server device directlyconnected to it (e.g., based on determining that the message does notinclude a destination connection data field, based on determining that adestination connection data field of the message indicates a directconnection of the client device, etc.). The client device may determinethe identity of the server device from which the message was originated,for example, by identifying a direct connection record, in theconnection database table of the client device, whose connection datafield indicates the direct connection identifier (e.g., as indicated inthe message). The client device may use the identity of server devicefor future communications (e.g., associated with the message).

If the client device is not directly connected to the first serverdevice (step 1003: N), the method may proceed to step 1005. In step1005, the first server device may set the forwarding flag anddestination connection identifier for the message to be sent to theclient device. For example, the first server device may update aforwarding flag data field of the message with a forwarding flag. Thefirst server device may search its connection database table todetermine the virtual connection to the client device, and may determinethe identifier of a connection between a server device directlyconnected to the client device and the client device. The first serverdevice may update a destination connection data field of the messagewith the identifier of that connection.

In step 1009, the first server device may send the message to the serverdevice directly connected to the client device. The server devicedirectly connected to the client device may act as an intermediateserver device configured to forward the message to the client device. Instep 1011, the server device directly connected to the client device(acting as the intermediate server device) may receive the message. Instep 1013, the intermediate server device may extract the forwardingflag from the forwarding flag data field of the message, and may extractthe destination connection identifier from the destination connectiondata field of the message. The forwarding flag may indicate, to theintermediate server device, that the message is to be forwarded.Additionally or alternatively, the intermediate server device may unsetthe forwarding flag of the message (e.g., updating the forwarding flagdata field of the message with a non-forwarding flag or removing theforwarding flag data field from the header of the message), and mayoverride the destination connection identifier in the message with anorigin connection identifier. The origin connection identifier maycomprise an identifier of a connection between the first server deviceand the intermediate server device.

In step 1015, the intermediate server device may determine theconnection to the client device based on the destination connectionidentifier, and may send the message to the client device via theconnection. In step 1017, the client device may receive the message. Forexample, the message may comprise a request, from the first serverdevice, for running status data of the client device, and/or any othertype of message. Additionally or alternatively, the receipt of themessage by the client device from the first server device may confirmthat the bidirectional communication channel between the first serverdevice and the client device has been established. The client device mayinspect the header content of the message. The header content of themessage may indicate that the message is not to be forwarded by theclient device, and may indicate the origin connection identifier. Theclient device may determine that the message was sent via a virtualconnection (e.g., based on determining that the origin connectionidentifier does not correspond to a direct connection of the clientdevice). The client device may determine, based on the origin connectionidentifier, the virtual connection via which the message was sent,and/or the identity of the server device from which the message wasoriginated (e.g., by identifying a virtual connection record, in theconnection database table of the client device, whose destinationconnection data field indicates the origin connection identifier). Theclient device may use the identity of server device for futurecommunications (e.g., associated with the message).

FIG. 11 is a flowchart showing an example method for providingbidirectional communications between server devices and client devices.In step 1101, a first server device, of a cluster of server devices,comprising one or more processors and memory may establish bidirectionalconnections with other server devices of the cluster of server devices.In step 1103, the first server device may establish a bidirectionalconnection with a client device. In step 1105, the first server devicemay form a virtual connection between the client device and a secondserver device of the cluster of server devices. The virtual connectionmay allow bidirectional communication between the client device and thesecond server device via the first server device. In step 1107, thefirst server device may receive, from the client device, a messagecomprising a header that includes forwarding flag data and destinationconnection data. In step 1109, the first server device may send, basedon the forwarding flag data and the destination connection data, themessage to the second server device.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are described asexample implementations of the following claims.

What is claimed is:
 1. A method comprising: establishing, by a firstserver device of a cluster of server devices, bidirectional connectionswith other server devices of the cluster of server devices;establishing, by the first server device, a bidirectional connectionwith a client device to form a virtual connection between the clientdevice and a second server device of the cluster of server devices,wherein the virtual connection allows bidirectional communicationbetween the client device and the second server device via the firstserver device; receiving, from the client device, a message comprising aheader that includes forwarding flag data and destination connectiondata; and sending, by the first server device and based on theforwarding flag data and the destination connection data, the message tothe second server device.
 2. The method of claim 1, wherein the sendingthe message to the second server device comprises: based on determiningthat the forwarding flag data indicates a forwarding flag, determining,based on the destination connection data, a connection to the secondserver device; updating the forwarding flag data with a non-forwardingflag, wherein the non-forwarding flag indicates, to the second serverdevice, processing a payload of the message; and sending the message,via the connection, to the second server device.
 3. The method of claim1, further comprising: receiving, by the first server device and fromthe client device, a second message comprising a second header thatincludes second forwarding flag data; and based on determining that thesecond forwarding flag data indicates a non-forwarding flag, processinga payload of the second message.
 4. The method of claim 1, furthercomprising: determining, based on a connection database table, that asecond client device is directly connected to the first server devicevia a second bidirectional connection; and sending, by the first serverdevice, to the second client device, and via the second bidirectionalconnection, a second message.
 5. The method of claim 1, furthercomprising: determining, based on a connection database table, that asecond client device is connected to the first server device via avirtual connection comprising a third server device of the cluster ofserver devices; populating forwarding flag data of a second message witha forwarding flag; populating destination connection data of the secondmessage with a connection between the third server device and the secondclient device; and sending, by the first server device and to the thirdserver device, the second message.
 6. The method of claim 1, furthercomprising: storing, by the first server device, a connection databasetable indicating a plurality of virtual connections to a plurality ofclient devices directly connected to the other server devices.
 7. Themethod of claim 1, further comprising: receiving, by a content switcherand from the client device, a connection request indicating anidentifier associated with the client device; and routing, by thecontent switcher and based on the identifier, the connection request tothe cluster of server devices; wherein the establishing thebidirectional connection with the client device is based on theconnection request.
 8. The method of claim 1, further comprising basedon the establishing the bidirectional connection with the client device:updating the client device with information associated with virtualconnections to the other server devices; and updating the other serverdevices with information associated with a virtual connection to theclient device.
 9. The method of claim 1, wherein each of thebidirectional connection with the client device and the bidirectionalconnections with the other server devices comprises one of a WebSocketconnection, a HTTP persistent connection, or a Comet connection.
 10. Afirst computing device, of a cluster of computing devices, comprising:one or more processors; and memory storing instructions that, whenexecuted by the one or more processors, cause the first computing deviceto: establish bidirectional connections with other computing devices ofthe cluster of computing devices; establish a bidirectional connectionwith a client device to form a virtual connection between the clientdevice and a second computing device of the cluster of computingdevices, wherein the virtual connection allows bidirectionalcommunication between the client device and the second computing devicevia the first computing device; receive, from the client device, amessage comprising a header that includes forwarding flag data anddestination connection data; and send, based on the forwarding flag dataand the destination connection data, the message to the second computingdevice.
 11. The first computing device of claim 10, wherein theinstructions, when executed by the one or more processors, further causethe first computing device to send the message to the second computingdevice by: based on determining that the forwarding flag data indicatesa forwarding flag, determining, based on the destination connectiondata, a connection to the second computing device; updating theforwarding flag data with a non-forwarding flag, wherein thenon-forwarding flag indicates, to the second computing device,processing a payload of the message; and sending the message, via theconnection, to the second computing device.
 12. The first computingdevice of claim 10, wherein the instructions, when executed by the oneor more processors, further cause the first computing device to:receive, from the client device, a second message comprising a secondheader that includes second forwarding flag data; and based ondetermining that the second forwarding flag data indicates anon-forwarding flag, process a payload of the second message.
 13. Thefirst computing device of claim 10, wherein the instructions, whenexecuted by the one or more processors, further cause the firstcomputing device to: determine, based on a connection database table,that a second client device is directly connected to the first computingdevice via a second bidirectional connection; and send, to the secondclient device and via the second bidirectional connection, a secondmessage.
 14. The first computing device of claim 10, wherein theinstructions, when executed by the one or more processors, further causethe first computing device to: determine, based on a connection databasetable, that a second client device is connected to the first computingdevice via a virtual connection comprising a third computing device ofthe cluster of computing devices; populate forwarding flag data of asecond message with a forwarding flag; populate destination connectiondata of the second message with a connection between the third computingdevice and the second client device; and send, to the third computingdevice, the second message.
 15. The first computing device of claim 10,wherein the instructions, when executed by the one or more processors,further cause the first computing device to: store a connection databasetable indicating a plurality of virtual connections to a plurality ofclient devices directly connected to the other computing devices. 16.The first computing device of claim 10, wherein the instructions, whenexecuted by the one or more processors, further cause the firstcomputing device to: receive a connection request indicating anidentifier associated with the client device, wherein the connectionrequest is routed to the cluster of computing devices based on theidentifier; wherein the establishing the bidirectional connection withthe client device is based on the connection request.
 17. The firstcomputing device of claim 10, wherein the instructions, when executed bythe one or more processors, further cause the first computing device to,based on the establishing the bidirectional connection with the clientdevice: update the client device with information associated withvirtual connections to the other computing devices; and update the othercomputing devices with information associated with a virtual connectionto the client device.
 18. The first computing device of claim 10,wherein each of the bidirectional connection with the client device andthe bidirectional connections with the other computing devices comprisesone of a WebSocket connection, a HTTP persistent connection, or a Cometconnection.
 19. One or more non-transitory computer readable mediastoring computer readable instructions that, when executed, cause afirst computing device of a cluster of computing devices to: establishbidirectional connections with other computing devices of the cluster ofcomputing devices; establish a bidirectional connection with a clientdevice to form a virtual connection between the client device and asecond computing device of the cluster of computing devices, wherein thevirtual connection allows bidirectional communication between the clientdevice and the second computing device via the first computing device;receive, from the client device, a message comprising a header thatincludes forwarding flag data and destination connection data; and send,based on the forwarding flag data and the destination connection data,the message to the second computing device.
 20. The one or morenon-transitory computer readable media of claim 19, wherein the computerreadable instructions, when executed, further cause the first computingdevice to send the message to the second computing device by: based ondetermining that the forwarding flag data indicates a forwarding flag,determining, based on the destination connection data, a connection tothe second computing device; update the forwarding flag data with anon-forwarding flag, wherein the non-forwarding flag indicates, to thesecond computing device, processing a payload of the message; and sendthe message, via the connection, to the second computing device.